HELLO I HAVE A SONY ERICSSON I BOUGHT FROM CELLCOM ISRAEL AND SINCE I CHANGED PROVIDER NOW I AM AT ORANGE I WOULD LIKE TO AN BLOCK MY PHONE THAT I AM STILL PAYING AND FOR WHICH CELLCOM DOES NOT CARE TO...
Almost all provider have contracts. Upon acquiring the plan, of any value an length, a contract(that binds you to the service provider) is signed by you. Most of these contract states the length of the Lock-in period, which you should be on their network. Some network provider even prohibits the "unlocking" of the phone for use on other networks. In short, the contract states that the unit or phone should be ONLY used on their networks during and until the prescribed lock-in period.
Sometimes, even if you pay for their services continually, and the network provider finds out(there are several ways for them to know) that you have used the unit against the signed contract(breach of contract- or violation of the terms and conditions) or simply have made the phone unlocked to use OTHER sim from other provider, the company or network provider CAN do whatever they may see as appropriate. Such as "BLOCKING" the phone and sometimes issuing a warning that you have violated the terms and condition, stated in the contract.
I suggest that you read the contract, or clear up with your original provider, with the terms.
It is with those terms, CELLCOM does not want to unblock your phone. If your handset comes with a plan with them, it would be clear on the contract you have signed, on how the handset should be used ONLY on their networks.
Unless you have bought the phone, without any plan or subscription, you may opt to do network changing anytime. And use it to any network you wish.
Unlocking the phone and using it other than the original network is a clear violation, and network providers have the right to lock(blacklist your phone), SOMETIMES even if you are still paying for it.
Hope this helps. Thank you for using Fixya.